U.S. intelligence and Homeland Security officials have said that social media campaigns by extremist groups such as ISIS and al Qaeda have fueled recruitment to their ranks and inspired lone wolves in cities including Paris, Copenhagen, Ottawa and Boston.

"Societies have to provide an affirmative alternative to extremist groups," Biden said, "and one that discredits the terrorist appeal to fear, isolation and resentment."

The vice president upheld as examples the work of Boston, Los Angeles and Minneapolis, where the Justice Department has launched a series of pilot programs involving local religious leaders, law enforcement and advocacy groups. Administration officials said one goal of the conference was for leaders from those cities to share best practices with others.

"The most important lesson we’ve learned, and we don’t always practice it, but it’s that inclusion counts," Biden said of the need to effectively integrate minority immigrant groups into American society, particularly Muslims. "Let me say it again: Inclusion counts. Inclusion counts."

"Inclusion counts." -VP Biden on the need to include all communities across the country in countering violent extremism

"I’m not talking about surveillance. I’m not talking about cameras," he said. "At the end of the day, it’s about treating each other with respect. ... Although we need technology, technology cannot replace contact."

"National security flows from a sense of community,” Biden added. “It’s not easy, but we have some significant experience, and I hope we can expand on it."

On Wednesday, the White House will host a series of panel discussions on violent extremism, including a session on strategies to amplify counter-messages on social media. President Obama is expected to address the gathering.